In 1926, Forrest Ackerman, a nine-year-old misfit in Los Angeles, visited a newsstand and bought a copy of Amazing Stories—a new magazine about aliens, monsters, and other oddities. By the time he reached the final page, he had become America’s first fanboy. He started a group called the Boys’ Scientifiction Club; in 1939, he wore an outer-space outfit to a convention for fantasy aficionados, establishing a costuming ritual still followed by the hordes at Comic-Con. Ackerman founded a cult magazine, Famous Monsters of Filmland, and, more lucratively, became an agent for horror and science-fiction writers. He crammed an eighteen-room house in Los Feliz with genre memorabilia, including a vampire cape worn by Bela Lugosi and a model of the pteranodon that tried to abscond with Fay Wray in “King Kong.” Ackerman eventually sold off his collection to pay medical bills, and in 2008 he died. He had no children.

But he had an heir. In 1971, Guillermo del Toro, the film director, was a seven-year-old misfit in Guadalajara, Mexico. He liked to troll the city sewers and dissolve slugs with salt. One day, in the magazine aisle of a supermarket, he came upon a copy of Famous Monsters of Filmland. He bought it, and was so determined to decode Ackerman’s pun-strewed prose—the letters section was called Fang Mail—that he quickly became bilingual.

Del Toro was a playfully morbid child. One of his first toys, which he still owns, was a plush werewolf that he sewed together with the help of a great-aunt. In a tape recording made when he was five, he can be heard requesting a Christmas present of a mandrake root, for the purpose of black magic. His mother, Guadalupe, an amateur poet who read tarot cards, was charmed; his father, Federico, a businessman whom del Toro describes, fondly, as “the most unimaginative person on earth,” was confounded. Confounding his father became a lifelong project.

Before del Toro started school, his father won the Mexican national lottery. Federico built a Chrysler-dealership empire with the money, and moved the family into a white modernist mansion. Little Guillermo haunted it. He raised a gothic menagerie: hundreds of snakes, a crow, and white rats that he sometimes snuggled with in bed. Del Toro has kept a family photograph of him and his sister, Susana, both under ten and forced into polyester finery. Guillermo, then broomstick-thin, has added to his ensemble plastic vampire fangs, and his chin is goateed with fake blood. Susana’s neck has a dreadful gash, courtesy of makeup applied by her brother. He still remembers his old tricks. “Collodion is material used to make scars,” he told me. “You put a line on your face, and it contracts and pulls the skin. As a kid, I’d buy collodion in theatrical shops, and I’d scar my face and scare the nanny.”

Del Toro filled his bedroom with comic books and figurines, but he was not content to remain a fanboy. He began drawing creatures himself, consulting a graphic medical encyclopedia that his father, an unenthusiastic reader, had bought to fill his gentleman’s library. Del Toro was a good draftsman, but he knew that he would never be a master. (His favorite was Richard Corben, whose drawings, in magazines such as Heavy Metal, helped define underground comics: big fangs, bigger breasts.) So del Toro turned to film. In high school, he made a short about a monster that crawls out of a toilet and, finding humans repugnant, scuttles back to the sewers. He loved working on special effects, and his experiments with makeup grew outlandish. There is a photograph from this period of del Toro, now overweight, transformed into the melting corpse of a fat woman; his eyeballs drip down his cheeks like cracked eggs. (“It’s a gelatine,” he recalled. “It looks messy, but it’s all sculpted.”)

He attended a new film school, the Centro de Investigación y Estudios Cinematográficos, in Guadalajara, and after graduating, in 1983, he published a book-length essay on Alfred Hitchcock. (Discussing “The Birds,” del Toro notes that “in the terror genre, an artist, unbound by ‘reality,’ can create his purest reflection of the world—the cinematic equivalent of poetry.”) In 1985, he launched Necropia, a special-effects company, making low-end bogeymen for films being shot in Mexico City. “Producers would call me on Friday and say, ‘We need a monster on Tuesday,’ ” he said. In 1993, he released his first feature, “Cronos,” about a girl whose tenderness for her grandfather deepens after he becomes a vampire. The girl has her abuelo sleep in a toy box, not a coffin, and pads it with stuffed animals. The grandfather doesn’t want to kill, and his predicament is captured with grim humor; at one point, he licks the results of a nosebleed off a bathroom floor.

“Cronos” won an award at Cannes, and del Toro began working in Hollywood, where monster design was in a torpid state. The last major period of innovation dated back to 1979, when the Swiss artist H. R. Giger unveiled his iconic designs for Ridley Scott’s “Alien.” The titular beast’s head resembles a giant dripping phallus, and for years afterward monster designers emulated Giger’s lurid sliminess. In 1982, the effects technicians Stan Winston and Rob Bottin slathered the spastic creatures of “The Thing” with Carbopol, a polymer used in personal lubricants; four years later, in “The Fly,” Jeff Goldblum’s skin sloughs off, revealing the gelatinous insect within.

Del Toro embraced the cliché with his first studio feature, “Mimic” (1997), in which oozing giant insects overtake the New York subway system. But his subsequent monsters were strikingly original, combining menace with painterly beauty. Starting in 2004, he made two lush adaptations of the “Hellboy” comic-book series, which is about a clumsy horned demon who becomes a superhero and battles monsters. The vicious incisors of “tooth fairies” were offset by wings resembling oak leaves; the feathers of a skeletal Angel of Death were embedded with blinking eyes that uncannily echoed the markings on a peacock. A del Toro monster is as connected to a succubus in a Fuseli painting as it is to the beast in “Predator.” His films remind you that looking at monsters is a centuries-old ritual—a way of understanding our own bodies through gorgeous images of deformation.

The dark, sensual fairy tale “Pan’s Labyrinth” (2006), del Toro’s most heralded film, is not what is typically conjured by the phrase “monster movie.” As is often the case in del Toro’s work, the worst monsters are human beings. In the violent aftermath of the Spanish Civil War, a defiantly imaginative girl, Ofelia, recoils from her harsh life—her stepfather is a Fascist captain who tortures dissidents—and descends into a ravishing underworld of sprites and satyrs. Though she barely evades the jaws of a famished ogre, she ultimately finds comfort in this spectral realm. For del Toro, who jokes that he “never willingly goes outside,” fantasy, even violent fantasy, is a refuge. The story of Ofelia inverts the usual scheme of horror; it’s as if one of the teens in “A Nightmare on Elm Street” had fought to remain trapped inside the world of dreams.

Many contemporary filmmakers seem embarrassed by the goofiness of monsters, relegating them to an occasional lunge from the shadows. Del Toro wants the audience to gawk. In the Mexican film industry, he told me, “it was so expensive to create a monster that, even if it was cardboard, they showed it a lot.” For del Toro, one of the key moments of horror cinema is in “Alien,” when Harry Dean Stanton “cannot run because he is in awe of the creature when it’s lowering itself in front of him. It’s a moment of man in front of a totemic god.”

Del Toro has battled to get his opulent vision of monsters onscreen. Miramax, which financed “Mimic,” found del Toro tediously arty and commissioned a second-unit director to add what del Toro calls “cheap scares.” He returned half his salary for “Hellboy,” and his entire salary for “Pan’s Labyrinth,” because he insisted on creature effects that his backers considered too expensive.

“Pan’s Labyrinth” received an Oscar nomination for Best Foreign Language Film, but del Toro refused to reposition himself as a highbrow auteur. His next film was the hectic “Hellboy II.” As del Toro has put it, “There is a part of me that will always be pulp.” He may be proudest of his schlockiest creations, such as the vampire Nomak, in “Blade II” (2002), whose toothy mouth folds open sideways, like labia, forming the ultimate vagina dentata; or the behemoth plant of “Hellboy II” (2008), which ravages Lower Manhattan like a greenhouse Godzilla. The plant monster’s demise is one of the most memorable in movie history: it spurts emerald blood that covers everything it touches in a lush carpet of moss. Del Toro does not worry that such fancies will sully his reputation. “In emotional genres, you cannot advocate good taste as an argument,” he said.

Although del Toro makes suspenseful movies, he often seems less like a disciple of Alfred Hitchcock than of Hieronymus Bosch. “I don’t see myself ever doing a ‘normal’ movie,” del Toro said. “I love the creation of these things—I love the sculpting, I love the coloring. Half the joy is fabricating the world, the creatures.” The movie that he most longs to make is an adaptation of a grandly ridiculous H. P. Lovecraft novella, “At the Mountains of Madness,” in which explorers, venturing into Antarctica, discover malevolent aliens in a frozen, ruined city. Some of the aliens mutate wildly, which would allow del Toro to create dozens of extreme incarnations. He said, “If I get to do it, those monsters will be so terrifying.”

Del Toro, now forty-six, owns a mock-Tudor mansion in Westlake Village, a sterile suburb northwest of Los Angeles. The house, which is a three-minute drive from an equally large house where he lives with his wife, Lorenza, and their two daughters, functions as his office, but it’s also a temple to his obsession with collecting—Forrest Ackerman’s mansion reborn.

Even outside, there are ghoulish touches. A weathervane on the roof is a dragon, and the front windowpanes are darkly tinted, suggesting a serial killer deflecting the postman. A sign on the lawn announces the estate’s formal name: Bleak House. Del Toro calls the place his “man cave.”

I knocked, and an assistant hollered for me to come in. When I opened the door, a rectangle of California sunshine invaded the dark entryway, landing on the hideous face of a large, lunging demon. It was a life-size cast-resin model of Sammael, from “Hellboy,” standing where a decorator would have placed a welcoming spray of flowers. Behind it, French doors offered a shimmery view of the back-yard pool. Sammael was far from the only model on display. Del Toro had filled the house with dozens of monster maquettes from his films—scale models created by special-effects shops during the early design phase, allowing the imaginary to become palpable. Del Toro had given Sammael, who has a lion’s mane of writhing tentacles, a subtle motif of asymmetry; one front limb is slightly longer than the other, setting his gait off balance, and he has an extra eye on the right side of his snout. Doug Jones, a mime turned actor who has played creatures in dozens of films, including “Hellboy” and “Pan’s Labyrinth,” says that, in the subculture of monster design, del Toro’s creatures are couture. “It’s because he’s a fanboy,” he said. “He knows exactly how fanboys critique movies. He anticipates the ‘That wouldn’t really work!’ response.”

I heard a heavy shuffling sound: del Toro, who at the time weighed more than three hundred pounds, was coming from a back room. (As Doug Jones observes, “Guillermo doesn’t pick up his feet when he walks.”) Del Toro gave me a genial slap on the back, his hand like a bear paw. Bleak House, he said, had been “inspired by Forry Ackerman,” who had been his “hero of heroes.” He said, “He was so nice! If you called him in advance, he would let you come to the house. Then he’d take you out for a slice of cherry pie.” Del Toro wore black sweatpants, a black T-shirt, and an unzipped black hoodie, all of which had been laundered so many times that they had faded into clashing inky shades. He had large ice-blue eyes, round glasses, and the rubbery cheeks of a kindergartner. An unruly brown beard, touched with gray, grounded him in manhood. A film of perspiration on his forehead trapped strands of hair that were supposed to be combed to the side.

Looming over the entryway was a huge contemporary painting of St. George and the Dragon, by a Russian painter named Viktor Safonkin. A curator at MOMA would cringe, but del Toro had keyed in on the originality of Safonkin’s dragon: all tail and no body, it coiled around St. George’s horse like a giant eel. Dragons, he told me, were his “favorite mythological animal,” and he was finally getting to design one: Smaug, the talking serpent who hoards the treasure in J. R. R. Tolkien’s “The Hobbit.”

Del Toro, in the biggest project of his career, had signed on to direct two films based on the novel. The project had already received enormous publicity, but, curiously, it did not yet have a green light. The film rights to “The Hobbit” were shared by New Line Cinema and M-G-M, and M-G-M, which had amassed a crippling $3.7-billion debt, could not finance a blockbuster project. But “The Hobbit” was likely to be a huge moneymaker, and del Toro felt certain that funds would be forthcoming. Peter Jackson, who had directed the “Lord of the Rings” trilogy, was an executive producer of the “Hobbit” films. After Jackson declared that he had no interest in directing five movies set in Middle Earth, del Toro was named his successor.

Del Toro, with his ornate aesthetic, was hardly the obvious choice to follow Jackson, who in his trilogy had placed Tolkien’s mythological characters in realistic landscapes—one worried about Frodo’s furry toes getting frostbite as he trudged through heavy snow. As del Toro put it, Jackson had reconstructed the Battle of Mordor with the same exactitude as the Battle of Gallipoli. Del Toro described his own style as more “operatic.” Speaking of Tolkien, he said, “I never was a mad fan of the ‘Rings’ trilogy.” “The Hobbit,” he said, “is much less black-and-white. The monsters are not just evil. They’re charming, funny, seductive. Smaug is an incredibly smart guy!” Del Toro later said that he inevitably imposed his sensibility on source material: “It’s like marrying a widow. You try to be respectful of the memory of the dead husband, but come Saturday night . . . bam.”

He began to show me around Bleak House. The windows had blood-red curtains and shirred blinds, giving the place a bordello vibe. In the downstairs library, the shelves were rigorously taxonomized. “This is Vampire Fiction,” he said, pointing to a row of books. “And this is Vampire Fact.” He picked up an aged leather-bound volume. “This is a treatise on vampirism, probably one of the best ones ever published, from 1759.” The book, “Dissertations Upon the Apparitions of Angels, Dæmons, and Ghosts, and Concerning the Vampires of Hungary, Bohemia, Moravia, and Silesia,” was printed in Paris and helped establish the idea that vampirism was contagious. (“Those who have been sucked suck also in their turn.”) Del Toro, who has inflexible preferences when it comes to vampires, admires the Polish folkloric tradition, in which erotic fangs are replaced by vile stingers. “They are the nastiest creatures,” he said. “Nothing romantic about them.” In 2009, he co-wrote a novel, “The Strain,” a gory update of the Polish typology—and a riposte to the swoony “Twilight.”

We headed upstairs, del Toro adopting the hushed garrulity of a docent. The walls were crowded with framed images, as at the Barnes Foundation, except in this case the collection featured Edward Gorey illustrations, concept-art sketches of the demon from “Fantasia” (“I’m an obsessive Disney-villain guy”), and comic-book panels, including a Richard Corben drawing of a mutant with four breasts. Del Toro himself still drew. “I cannot learn technique from Caravaggio and those guys—how they did it, I have no idea,” he said. “That’s why I started collecting original illustrations. I wanted to see the brushstroke or the Wite-Out. Then I could understand how they did it.”

Over a doorframe, del Toro had hung a Magic Marker skeleton drawn by his older daughter, Mariana, now fourteen. She “comes here to play,” he said; his younger daughter, Marisa, who is nine, found Bleak House too frightening. Lorenza, a former veterinary surgeon who is now a homemaker, met del Toro when they were in high school. They had a shared interest in animal anatomy. For a while, she assisted him with his makeup designs. (Uxoriousness, as expressed by del Toro: “She was the best foam technician I’ve ever had.”) It was Lorenza who had transformed him into the leaky-eyed corpse, for a Mexican television show.

The show’s script had been silly, he recalled, but when it came to horror it was foolish to focus on dialogue: “Some of the most immortal things in our glossary of images come from movies with not necessarily the greatest screenplays.” He refers to a script as a “libretto”; horror, he said, is special because it “excites a nonverbal part of us.” He mentioned Kubrick’s “The Shining”: “You’re reading, ‘Danny rides his tricycle through the corridors.’ You just don’t get it—how lonely they are, the rhythm of the prrr, the change of frequency in the wheels, the pattern in the carpet going frh, frh, frh, the lens enhancing the field and the perspective, and the moment he turns the corner the twins being there. You can’t explain that in words.” Del Toro often spends months planting “visual rhymes” in his movies; the tunnels that Ofelia travels through in “Pan’s Labyrinth,” for example, all have “feminine apertures.” What others call eye candy del Toro calls “eye protein.”

We went back downstairs, and del Toro gently tapped a glass panel covering a mounted Malaysian stick bug; its rigid abdomen was nearly a foot long. He had bought the bug at Maxilla & Mandible, the famous Manhattan emporium, on a childhood visit to New York, and its form had steeped in his imagination. Two decades later, it inspired a key sequence in “Pan’s Labyrinth.” In her first glimpse of magic, Ofelia witnesses a stick bug on her bed change into a chattering pixie. “That’s why I collect images,” he said. “All this stuff feeds you back.”

In an adjoining hallway, he pushed on a bookcase: the inevitable hidden door. A severed leg, from “Cronos,” was propped near the fireplace. Del Toro picked it up and smiled. “This is complete with fake hair!” he said. “We used to do this at Necropia. You put the hair through a hypodermic needle and inject it.” While running Necropia, he worked regularly on “Hora Marcada,” a Mexican homage to “The Twilight Zone.” In one episode, del Toro played an ogre who befriends a child; the show was directed by Alfonso Cuarón, who later made “Y Tu Mamá También.” They became good friends, and essential editors of each other’s work. The ménage-à-trois scene near the end of “Mamá” was del Toro’s idea.

The latest addition to Bleak House was a clockwork automaton of a skeleton playing the accordion, which del Toro had bought for sixteen thousand dollars. He has said of his fetish for the macabre, “It’s as hard to explain as a sexual proclivity. Some guys like high-heeled shoes. I like horror.” The size of the collection was disconcerting; it was as if the 40-Year-Old Virgin had been handed a three-million-dollar decorating budget. Del Toro owned more than five thousand comic books and several puppets of Nosferatu. On a shelf, a posed plastic figurine of Leatherface, from “The Texas Chainsaw Massacre,” battled Edward Scissorhands. A life-size statue of Boris Karloff, in the guise of Frankenstein’s Creature, lurked in a corner of the dining room. At one point, del Toro issued the apt warning, “This is the room where I keep most of my aliens.”

The kitchen had no food other than a box of crackers. But, just as Carrie Bradshaw stored Manolos in her oven, del Toro had slyly repurposed the kitchen into a museum of anatomical models. Fetuses crowded the counters. As a young child, del Toro had read a book featuring laparoscopic photographs of babies in utero; the images eventually provided a visual rhyme for “The Devil’s Backbone” (2001), a ghost story set during the Spanish Civil War. (A doctor keeps a collection of jarred mutants; the ghost drowns a villain in a pool that has the golden tinge of amniotic fluid.) Del Toro then shared a story that, like many tales he tells about his Mexican youth, had the polished feel of a fable.

“I saw a guy with a split skull walking down the street,” he said. “The guy wasn’t mentally stable, because somebody had hit him, and I took him to the hospital. And they said, ‘We’ll take care of him.’ I came back the next morning, and they said, ‘We returned him to the mental ward.’ So I went there, and they said that he escaped in the night. I went to the director and I said, ‘What kind of hospital is this?’ And she said, ‘Look, if you have something to say about it, come and volunteer.’ So I got to know the embalmers. One day I visited, and there was a pile of fetuses, new arrivals. Maybe it’s magnified in my memory, but I remember it being this tall.” He lifted his arm to his waist.

Del Toro had been raised Catholic, but this sight, he said, upended his faith. Humans could not possibly have souls; even the most blameless lives ended as rotting garbage. He became a “raging atheist.” Guadalajara was a rough place, and he recalled his childhood as a slide show of harrowing images: the decapitated body of a teen-age boy, found by a barbed-wire fence; a crashed motorist aflame inside his VW Beetle. Del Toro said, “People tell me, ‘Oh, you must love forensic photos.’ But I can’t stand the sight of real pain or blood.”

At one point, I asked him why he no longer lived in Mexico. He explained that, in 1998, his father had been kidnapped by bandits for seventy-two days. After the family paid two ransoms, Federico was released, and Guillermo moved his family to America. Although the experience was wrenching, he observed, “I highly recommend you save your father’s life. You don’t see yourself as somebody’s child anymore. You become a man saving another man.” He claimed that the experience had ended his “perpetual puberty.”

We walked past a display case of Star Wars aliens, and returned to the front door. Del Toro told me that, in a few weeks, he’d be locking up Bleak House for a while. He was taking his family with him to New Zealand, where filming for “The Hobbit” was to begin once he had finished designing dozens of costumes and creatures. The production-design work would be completed at Weta Digital—the Wellington visual-effects firm that Jackson co-founded, and that created much of the dreamscape of James Cameron’s “Avatar.”

For several months, del Toro said, he had been working on the dragon. “It will be a very different dragon than most,” he said. He proposed discussing it over lunch. He went upstairs to retrieve several notebooks. “I keep my journals locked in a safe in my bathroom,” he said abashedly, as if this had been the afternoon’s sole display of eccentricity. As we left, I noticed that several boxes of eye protein from Amazon—comic books, DVDs, model kits—had been tossed onto the floor before Sammael’s gaping maw.

We drove east to Burbank. Del Toro is devoted to the Valley—he calls it “that blessed no man’s land that posh people avoid in L.A.” We pulled into Ribs U.S.A., a frayed establishment on Olive Avenue. Del Toro ordered ribs and a lemonade, along with a redundant appetizer of “riblets.”

He told me that each of his notebooks was “an art project in itself.” He’d bought seven leather-bound journals at an antiquarian bookstore in Venice. I opened up his current notebook, which included sketches for “The Hobbit,” while he put on a plastic bib bearing the inscription “I ♥ RIBS.” Ink drawings of creatures were surrounded by text that jumped between Spanish and English: captions, musings, story ideas. The first drawing I saw was titled “Peces Sin Ojos”—“Fish Without Eyes.” Del Toro writes with a fountain pen, and lately he has used a Montblanc ink the color of blood. The over-all effect is that of a Leonardo codex.

I paused at what looked like an image of a double-bitted medieval hatchet. “That’s Smaug,” del Toro said. It was an overhead view: “See, he’s like a flying axe.” Del Toro thinks that monsters should appear transformed when viewed from a fresh angle, lest the audience lose a sense of awe. Defining silhouettes is the first step in good monster design, he said. “Then you start playing with movement. The next element of design is color. And then finally—finally—comes detail. A lot of people go the other way, and just pile up a lot of detail.”

I turned to a lateral image of the dragon. Smaug’s body, as del Toro had imagined it, was unusually long and thin. The bones of its wings were articulated on the dorsal side, giving the creature a slithery softness across its belly. “It’s a little bit more like a snake,” he said. I thought of his big Russian painting. Del Toro had written that the beast would alight “like a water bird.”

Smaug’s front legs looked disproportionately small, like those of a T. rex. This would allow the dragon to assume a different aspect in closeup: the camera could capture “hand” gestures and facial expressions in one tight frame, avoiding the quivery distractions of wings and tail. (Smaug is a voluble, manipulative dragon; Tolkien describes him as having “an overwhelming personality.”) Smaug’s eyes, del Toro added, were “going to be sculpturally very hidden.” This would create a sense of drama when the thieving Bilbo stirs the beast from slumber.

Del Toro wanted to be creative with the wing placement. “Dragon design can be broken into essentially two species,” he explained at one point. Most had wings attached to the forelimbs. “The only other variation is the anatomically incorrect variation of the six-appendage creature”—four legs, like a horse, with two additional winged arms. “But there’s no large creature on earth that has six appendages!” He had become frustrated while sketching dragons that followed these schemes. The journal had a discarded prototype. “Now, that’s a dragon you’ve seen before,” he said. “I just added these samurai legs. That doesn’t work for me.”

Del Toro’s production design for “The Hobbit” seemed similarly intent on avoiding things that viewers had seen before. Whereas Jackson’s compositions had been framed by the azure New Zealand sky, del Toro planned to employ digital “sky replacement,” for a more “painterly effect.” Sometimes, instead of shooting in an actual forest, he wanted to shoot amid artificial trees that mimicked the “drawings in Tolkien’s book.” In his journal, I spied many creatures with no precedent in Tolkien, such as an armor-plated troll that curls into a ball of metal plates. Del Toro said that it would be boring to make a slavish adaptation. “Hellboy,” he noted, was based on a popular comic-book series, but he had liberally changed the story line, and the demon had become an emotionally clumsy nerd. “I am Hellboy,” he said.

Even the major characters of “The Hobbit” bore del Toro’s watermark. In one sketch, the dwarf Thorin, depicted in battle, wore a surreal helmet that appeared to be sprouting antlers. “They’re thorns—his name is Thorin, after all,” he said. The flourish reminded me of a similar arboreal creature in “Hellboy II,” which was slightly worrying. That film is so overpopulated with monsters that it begins to feel like a Halloween party overrun by crashers. Midway through the film, del Toro stages a delightful but extraneous action sequence in a creature-clogged “troll market” hidden beneath the Brooklyn Bridge. The scene comes across as del Toro’s bid to supplant the famous Cantina scene in “Star Wars.”

The ribs arrived, and after one bite del Toro pushed them aside. “They must have changed management,” he said sadly. He had frequented the place while editing “Cronos” and “Blade II” at a studio in the Valley.

He showed me some notebooks from that early period. One contained the first incarnation of the Pale Man, the ogre that chases Ofelia in “Pan’s Labyrinth.” A metaphor for gluttony, he is del Toro’s most personal creation, and the five wordless minutes in which he appears are among the scariest in modern cinema. Ofelia, wandering through a tunnel, encounters the Pale Man sitting motionless at the head of a banquet table covered with food. He is sickeningly thin, his chalky white skin hanging in drapelike folds. He has apparently been cursed—placed, like Tantalus, before objects of temptation. The Pale Man “came out of a really dark, primal place,” del Toro said. “I had lost weight, and I saw my belly sagging.”

He pointed at the notebook drawing, which depicted a wizened creature. Originally, he said, the ogre was “going to have an old man’s face,” to indicate that he had been cursed for centuries, but he “didn’t like how trivial it seemed.” To emphasize the Pale Man’s monomaniacal hunger, del Toro asked his designers to render the ogre’s face blank, except for a mouth and tiny nasal punctures. He told them, “Let’s take out the eyes and put them on a platter before him.” The eyes are an allusion to St. Lucy: “I saw a statue when I was a kid where she had the eyes on a little plate. That was pretty freaky, and I liked it.”

As Ofelia creeps through the banquet hall, she glances upward. A series of frescoes on the ceiling silently unfurls the story of the Pale Man. In one panel, a hearty-looking ogre devours a child, as in Goya’s painting of Saturn. Del Toro told me that, in imagining the monster, he had settled on a twisted rule: the Pale Man could “engage in gluttony only if a kid indulged in gluttony. If a kid broke the rule of not eating, then he could.” When Ofelia snatches a grape from the table, the curse is broken and the Pale Man quickens. In a sickening change of silhouette, the ogre picks the eyes off the plate and squishes them into his palms. Placing his hands in front of his face, like goggles, he pursues Ofelia with a shuffling gait, his outstretched fingers like grotesque eyelashes. The image, del Toro said, owes something to a poster for the trashy 1979 film “Phantasm,” in which the eyes of a screaming woman can be seen through the hands covering her face.

Closing the notebook, del Toro spoke about his struggles with his weight. His pants size was down from its peak, size 62, but he was concerned about the physical challenges of shooting on location in New Zealand. He worried that his next few films might be his last. Maybe it was time to resist temptation. Looking at the plate of uneaten ribs, he joked, “I’m not just Hellboy—I’m the Pale Man, too.”

Before decamping to New Zealand, del Toro checked in on another monster—a new version of Frankenstein’s Creature. Since childhood, he had dreamed of adapting Mary Shelley’s novel, which he considers a founding text of modern monster mythology. “Monsters exist only if the pretense of reason exists,” del Toro had told me. “Before the Age of Reason, you cannot generally claim monsters as an unnatural force. There were dragons on the map—as much of a fact as sunrise.” For someone like del Toro, giving birth to a new Frankenstein’s Creature is even more exciting than designing an original monster. Just as a Renaissance painter relished the challenge of rendering the Crucifixion, a true monster-maker wants to take on the icons.

“Frankenstein” was one of nearly a dozen projects that del Toro had in development. He hoped to follow “The Hobbit” with a spate of more personal films, including “Saturn and the End of Days,” a “deranged little movie” about a boy who witnesses the Rapture from his bedroom window. Del Toro is sometimes mocked for his tendency to announce projects prematurely. Recently, on the Hollywood news site Deadline, a commenter sniped, “This man is more famous for what he hasn’t done than what he has.”

To secure financing for “Frankenstein” from Universal, which signed a production deal with del Toro in 2007, he had to direct a “proof of concept” video: a brief sequence demonstrating that his Creature was thrilling enough to justify a new film. Though he had mentally sketched out the film, he hadn’t even begun a script. Everything would emanate from the monster’s design.

Work on Frankenstein’s Creature was being done at Spectral Motion, a design studio in a warehouse in Glendale. Most of del Toro’s monsters come to life there. When we arrived at the studio, del Toro was greeted by the company’s founder, Mike Elizalde, and they amiably exchanged curses in Spanish. Born in Mazatlán, Elizalde has the compact, muscled build of a superhero sidekick. He is a master of animatronics—making puppets move with robotics. With del Toro’s support, Spectral Motion has become an avant-garde studio for traditional monster design. It innovates with latex, not pixels.

We headed to the sculpting area, at the back of the warehouse. Monster maquettes were crammed atop bookshelves, like sports trophies in a locker room. A headless Hellboy suit hung on a gray mannequin. Desks were strewn with muscle magazines—the sculptors consult them when designing monster physiques. A torso lay on a long table, harshly illuminated by a swing lamp; several maquettes had been wrapped in black garbage bags, in preparation for storage. The place felt like a makeshift morgue.

At Spectral, a monster design is first rendered in clay. A mold is then made, and a plastic compound is poured into it to produce a maquette. Even when a creature is destined to be primarily computer-generated, del Toro commissions maquettes; seeing a beast in physical form helps him detect design flaws. Elizalde said that del Toro was by far his favorite client, because of “his tremendous imagination and appreciation for what can be done practically.” Many directors, Elizalde said, haplessly begged him to make something scary; del Toro provided blueprints from his notebooks, and assessed maquettes like a biologist supervising a dissection. They shared a distrust of excessive computerized effects, which often looked weightless onscreen. “That’s part of the goal of his films,” Elizalde said. “To celebrate the handmade, old-school creature.”

The “Frankenstein” project was tucked in a side room. Just before we got there, del Toro stopped short. “Is that the original casting?” he asked. On a high shelf sat a bust of Gill-man, from “Creature from the Black Lagoon.” One of Elizalde’s sculptors had borrowed the bust from an archive for close study. Del Toro, who considers Gill-man the apex of man-in-a-suit design, informed me that its creator was Milicent Patrick, a former Disney animator. Patrick did not receive official credit—apparently, nobody involved in “Lagoon” had wanted it known that a woman created the monster. Judging from the staff at Spectral, the demographics of monster design hadn’t changed much. Del Toro could recall working with only one female designer, on “Hellboy.” “This is a very geeky pursuit,” he said.

Sculpting Frankenstein’s Creature was Mario Torres, a slight, doleful-looking Latino whose head was covered by a navy-blue ski cap. For “Hellboy II,” he had helped del Toro design Mr. Wink, a troll with a mace for a fist. On Torres’s desk, near a small portable oven, was a large red clay bust of the Creature. Once the design was settled, the staff at Spectral Motion would use the bust as a guide for creating prosthetics that could be layered on an actor’s face.

In accordance with Mary Shelley’s description, the head appeared to have been stolen from a cadaver: there was exposed sinew around the jaw, and the cheekbones looked ready to poke through the scrim of flesh. Most appallingly, the Creature lacked a nose; a single bridge bone protruded over an oval breathing hole. Torres had been etching deep furrows into the Creature’s forehead, and shaved bits of clay were scattered on his desk, like clippings on a barbershop floor.

The Creature’s face was inspired, in part, by the graphic artist Bernie Wrightson, who, in 1983, published a stunning illustrated edition of “Frankenstein.” Four panels from the book hung in del Toro’s study at Bleak House. Wrightson’s Creature has been rudely cobbled together from several corpses, but he also has a lithe, sensual grace. It’s Michelangelo’s David, if Goliath had won.

For ten seconds, del Toro beheld the bust. “Que lástima,” he began—“What a shame.” Torres looked ready to pull his ski cap over his eyes. Del Toro unleashed a twenty-minute critique, largely in Spanish, lessening the sting with humor and pats on the back. “Cabrón, is that the nose of Skeletor?” he teased. The nose bridge was implausibly long, del Toro said. The facial decay was inconsistent: if the nostrils and underlying cartilage had rotted away, the earlobes would be long gone, too. “Anything that dangles goes away faster,” he noted. And the Creature’s furrowed expression was too limiting: “If it was going to be the monster just for a few minutes, I would say it’s really good. But it’s the main character.” The prosthetics for the Creature needed “to accommodate a personality,” allowing the actor wearing them to express “calm, vacancy, or even happiness.”

“So these lines are too deep?” Elizalde, who was taking notes, said.

“Yes,” del Toro said. “It needs to go beyond a good sculpture. You need to really believe.” He wanted fewer wrinkles across the face. “It has to convey being newborn.”

Del Toro studied the bust again, then told Torres that the jawline should be “bulked up” to look more square—it would be the single allusion to the famous Boris Karloff incarnation.

“Más Karloff,” Torres agreed, meekly.

The bust was modelled on the face of Doug Jones, the former mime, who had already agreed to play the role. Jones has performed as a monster so many times that Spectral Motion keeps a full-body cast of him on hand. Jones is prized by del Toro for his tiny head, swanlike neck, and spindly physique (six feet three, a hundred and forty pounds). Makeup artists can layer prosthetics on him without giving him a clunky silhouette. “Is this his real neck?” del Toro said of the bust, admiringly. “He’s inhuman!”

Elizalde asked del Toro about the Creature’s hair. Shouldn’t it be patchy, to emphasize the theme of decay?

“No, it should be long and full,” del Toro said. “He’s the Iggy Pop of Frankensteins!” He wiggled his hips. Shelley’s story had resonated with del Toro as a metaphor for the rebelliousness of teen-agers, and so he wanted the Creature to have the unnerving vitality of a rock star.

Del Toro turned to a nearby table, where he examined a green clay version of the Creature’s entire body. The figure, about a foot high, was lurching forward. “This is very twenty-first century,” he joked, pointing at the figure’s dangling penis.

“Lose it?” Elizalde asked.

“Yes,” del Toro said. “We’re going to have to make a gauze-cotton loincloth that is sort of falling off.” This would indicate that the monster “just came out of the lab table.” To underscore the Creature’s origin in multiple cadavers, one of the arms needed to be longer than the other.

He complained that the sculpture didn’t graphically indicate where the sutures were. “Give me the gauge,” he said to Torres. He grabbed the tool and, squinting, carved into the lower right hip; turning the sculpture wheel, he continued the line across the Creature’s buttocks. The suture lines, he told Torres, should “look jagged,” and the various body parts should have different skin tones.

Torres took some warm clay out of his oven and began Karloffing the jaw. Del Toro, scrutinizing the bust again, ordered a radical rhinoplasty: “Take this nose off.” He was questioning Wrightson’s breathing-hole concept. Later, he explained, “It’s a great graphic idea, but I’m not sure it works so much practically. When an actor acts with his eyes, you want to be looking at his eyes, not at a breathing plug-hole.” He requested a nose that looked semi-crushed and “about to slide off.”

Elizalde liked the idea. “It’s a cool effect, when you have that ridge of the bone, and you have tissue that’s sort of stringy and hanging on. It’ll be pretty creepy-looking.”

Torres asked, “How should the nose look on the inside?”

“Not like this!” del Toro said, patting him. “This is too Halloween.” He paused. “Don’t you have a skull around?” He flipped through Bone Clones, a catalogue of osteological replicas. “See? There are some very tiny, skinny bones in there.” Del Toro told Torres that he would return in four days, “to determine exactly what the nose area should look like.”

While we were in the sculpture studio, a pair of assistants filled del Toro’s Chrysler sedan with maquettes that had been polished for display at Bleak House. As del Toro emerged outside, the Angel of Death was being gingerly lowered into the back seat. “Es la Virgen María!” he said. Elizalde wished del Toro good luck in New Zealand. Del Toro climbed in and headed toward the freeway; a seat-belted maquette of Mr. Wink rode shotgun.

Shortly after that, del Toro and his family moved to Wellington, but he never shot a frame of “The Hobbit.” For nine months, he waited for a starting date, but M-G-M was unable to resolve its financial woes. In May, after the earliest possible release date for Part 1 slid back a year, to December, 2012, del Toro abruptly flew home to Los Angeles. A statement was released: “In light of ongoing delays in the setting of a start date for filming ‘The Hobbit,’ I am faced with the hardest decision of my life. After nearly two years of living, breathing and designing a world as rich as Tolkien’s Middle Earth, I must, with great regret, take leave from helming these wonderful pictures.”

A week later, I met with del Toro in a restaurant on New York’s Lower East Side. He was a bit sheepish, perhaps because his sudden departure raised the question of whether he had been fired. Since “The Lord of the Rings: The Return of the King” won eleven Oscars, Jackson had made two overblown messes, “King Kong” and “The Lovely Bones.” Revisiting Tolkien would allow him to rebound. And with Jackson in charge, “The Hobbit” could be presented to investors as a no-risk product. Though the studios initially announced that another successor would be found, Jackson soon signed on himself, and the green light came. Steve Cooper, one of the heads of M-G-M, said, “Under Peter’s direction, the films will undoubtedly appeal to fans of the original ‘L.O.T.R.’ trilogy.”

At the restaurant, del Toro had trouble squeezing into the booth; he had gained weight in Wellington. He was adamant that he had left “The Hobbit” of his own accord, but his language seemed careful. “The visual aspect was under my control,” he said. “There was no interference with that creation.” In collaboration with Jackson and two screenwriters, del Toro had completed drafts for Parts 1 and 2. But final revisions were still to come, and he noted that any “strong disagreements” between him and Jackson would have occurred when they debated which scenes to film and which to cut—“You know, ‘I want to keep this.’ ‘I want to keep that.’ ” But, he said, he had quit “before that impasse.” I asked him if there had been creative tension. At Weta, he said, the production delay had made everyone anxious, and he “could not distinguish between a real tension and an artificial tension.”

He admitted that there had been discomfort over his design of Smaug. “I know this was not something that was popular,” he said. He said that he had come up with several audacious innovations—“Eight hundred years of designing dragons, going back to China, and no one has done it!”—but added that he couldn’t discuss them, because the design was not his intellectual property. “I have never operated with that much secrecy,” he said of his time at Weta.

Del Toro said that it had hurt “like a motherfucker” to leave the production, but I got the sense that he had found it even more painful to be away from L.A. “I really missed my man cave,” he said. In an attempt to approximate his collections at Bleak House, assistants had shipped two dozen boxes of duplicate material to Wellington, but del Toro still felt as if he were in a sensory-deprivation tank. A different kind of man would have enjoyed being close to the New Zealand Alps, but del Toro, the ultimate indoorsman, rarely left Wellington. Being stuck in New Zealand caused him to lose important creative opportunities. He had agreed to launch a new animation label at Disney, Double Dare You, specializing in scary movies for kids, but the deal foundered during his absence.

The most difficult part, he said, was “making peace with the fact that somebody else is going to have control of your creatures, your wardrobe, and change it, or discard it, or use it. All options are equally painful.” He added, “The stuff I left behind is absolutely gorgeous. I’m absolutely in love with it.” He suddenly became animated, waving his hands in the air like a conductor navigating a treacherous passage of Mahler. “We created a big exhibit in the last few weeks, in preparation for a studio visit. I had color-coded the movie: there was a green passage, a blue passage, a crimson passage, a golden passage. In Tolkien, there is a clear season for autumn, winter, summer, spring in the journey. And I thought, I cannot just stay in four movements in two movies. It will become monotonous. So I thought of organizing the movie so you have the feeling of going into eight seasons. So a certain area of the movie was coded black and green, a certain area was crimson and gold, and when we laid out the movie in a big room, we had all the wardrobe, all the props, all the color-coded key art. When you looked and saw that beautiful rainbow, you could comprehend that there was a beautiful passage.” His scheme would probably be abandoned, he said later: “Not much is going to make it. That’s my feeling.” Would his art be returned to him? “I hope to get maquette visitation rights.” But he was grateful not to have them already at Bleak House; they would be a torment.

At the restaurant, he reminded me that the subtitle of “The Hobbit” is “There and Back Again.” He said, “There was a moment in the screenplay—I don’t know if it’s going to survive or not—where it was made clear that the purpose of the journey is for Bilbo to know that he wants to be home, to say, ‘I understand my place in the world.’ For me, the journey to New Zealand was like that.”

Del Toro had gone on a quest, but he came home with no treasure. The triumph of “Pan’s Labyrinth” was now five years old. He needed a comeback project. In Wellington, he hadn’t been able to film the proof-of-concept video for “Frankenstein.” That could be next. But he was thinking of taking an even bigger risk, and pursuing the adaptation of Lovecraft’s “At the Mountains of Madness”—his “Sisyphean project.” He had begun sketching images for an adaptation in 1993 and had completed a script in 1998. But the project had seemed too daunting; digital effects weren’t yet good enough to render creatures that changed shape far more radically than Transformers. Then, while del Toro was in Wellington, “Avatar” was released, and its landmark effects made “Madness” seem plausible. Crucially, James Cameron, a friend, had agreed to be a producer for “Madness,” sharing his expertise in designing strange worlds. And del Toro was now less wary of making digital monsters. At Weta, he had experimented with a “virtual camera,” which allows a director to maintain a sense of physicality when filming a C.G.I. creature. “They lay out the animation, you grab a camera, and you can change the angles within that virtual environment,” he said. “One day, I ended up dripping sweat from handling the virtual camera on the motion-capture stage. This camera would be very handy on ‘Madness.’ ”

The movie would not be an easy sell, though. Del Toro envisaged “Madness” as a “hard R” epic, shot in 3-D, with a blockbuster budget. Creating dozens of morphing creatures would be expensive, and much of the film needed to be shot somewhere that approximated Antarctica; one of the most disquieting aspects of Lovecraft’s novella is that the explorers are being pursued by monsters in a vast frozen void, and del Toro wanted to make the first horror movie on the scale of a David Lean production. But a “tent-pole horror film,” as del Toro put it, hadn’t been made in years. High-budget productions such as “Alien” and “The Shining” had been followed by decades of cheaper thrills. “The natural flaw of horror as a genre is that, ninety-nine per cent of the time, it’s a clandestine genre,” he said. “It lives and breathes—‘Texas Chainsaw Massacre,’ the first ‘Saw,’ ‘The Blair Witch Project’—in dark little corners that come out and haunt you. Rarely is there a beautiful orchid that blooms.” He mentioned Hitchcock’s “The Birds”: “It was a major filmmaker using cutting-edge optical technology and special effects. It was a big-budget movie. It had Edith Head designing costumes, it had all the luxuries. And it was appealing because it had all the polished aspects of a studio film.”

Del Toro thought that nearly all his previous movies had conveyed “sympathy for the monsters.” With “Madness,” he said, he would terrify the audience with their malignancy. First, though, he needed to make Universal executives feel that, in allowing del Toro to design a creature-filled world, they weren’t being reckless—rather, they were commissioning a variation on “Avatar,” the most successful film in history. “Studios look backward,” del Toro said. “Filmmakers look forward.”

To anybody who owns thousands of comic books, “At the Mountains of Madness” is as central to the American canon as “Moby-Dick.” H. P. Lovecraft, who was born in 1890 and died in 1937, wrote densely interlinked stories that convey “cosmic horror.” More than one tale features a giant tentacled alien named Cthulhu. Lovecraft refers to Cthulhu several times in “Madness,” and del Toro, in writing his script, had devised a way to integrate the iconic beast into the climax. (“Its membranous wings extend, filling the horizon, its abominable head silhouetted by lightning in the clouds!”) Del Toro could create a totemic god.

Although Lovecraft’s work was dismissed in his lifetime, contemporary writers including Stephen King and Joyce Carol Oates have celebrated him as the heir to Edgar Allan Poe. Lovecraft’s prose may have the highest adverbial density in English: “I saw the freshly glistening and reflectively iridescent black slime which clung thickly to those headless bodies and stank obscenely.” But, like an outsider artist, he is so committed to his lunatic visions that they achieve a strange grandeur.

In “Madness,” twenty Edwardian scientists sail from Tasmania to Antarctica in search of geological samples, and they discover a mountain range that dwarfs the Himalayas. On one summit is a hidden, ruined city whose bizarre architecture suggests that its inhabitants were not human. As the scientists explore the ice-encased structures, they discover “pictorial friezes” revealing an awful secret. Hyper-intelligent aliens, the Old Ones, landed on earth millions of years ago. Creating organic life forms as tools, the Old Ones fashioned every creature on the planet, including human beings. One of their inventions, shape-shifters known as Shoggoths, were intended as slaves; but the Shoggoths rebelled, slaughtering the Old Ones. After the explorers accidentally thaw a few surviving Old Ones, a hidden army of Shoggoths emerges from the shadows, and the humans find themselves caught in an alien war. Del Toro loves the story, in part because Lovecraft combines terror—the panicked effort to escape the creatures—with metaphysical horror: “The book essentially says how scary it is to realize that we are a cosmic joke.”

This past summer, Universal gave del Toro seed money, allowing him to create an “art room” for “Madness.” Once again, del Toro was designing creatures without a green light. By the end of the year, he would present his vision to the studio. If Universal executives said yes, he would start filming by June; if not, he would have provided more support for the parental claim that monsters don’t really exist.

I met with del Toro in Los Angeles on the first day of preproduction. He had hired five artists to engage in ten weeks of “design promiscuity” at Lightstorm, James Cameron’s production company, which is in Santa Monica. Parts of “Avatar” had been designed in the same suite of offices. Corkboards were covered with constellations of silver pushpins; in an interior room, “Avatar” maquettes were still on display.

Del Toro had transformed his own silhouette. He had lost twenty-seven pounds in three weeks, after undergoing sleeve-gastrectomy surgery. “They take three-quarters of your stomach out and throw it out!” he said. “I feel great.” That day, he had eaten a light lunch with his daughter Mariana, and in an elevator they had played a family game: Guillermo aimed his belly and crushed her, gently, into a corner. In Spanish, she lamented, “This game won’t be fun when you’re no longer fat.” Mariana, who is slender, has the flinty confidence of Thora Birch in “Ghost World”; she was toting an iPad, upon which she had sketched an apple-green, lizardy creature—a monster leavened with Nickelodeon cheer.

For the first few days, del Toro wanted his “Madness” artists to draw without precepts. These men had been sketching Shoggoths since junior high school. What had Lovecraft made them see? “Lovecraft is actually really stringent about describing the Old Ones,” he noted. “And his design is really hard to solve, because they are essentially winged cucumbers.”

He wanted the creatures in “Madness” to be fascinating, not disgusting. He said, “Normally, creatures are designed in the same way that gargoyles were carved in churches—for maximum shock value.” He cited Ray Harryhausen, a master of stop-motion animation, who designed the effects for the 1981 “Clash of the Titans”: “He used to say, ‘Whenever you think of a creature, think of a lion—how a lion can be absolutely malignant or benign, majestic, depending on what it’s doing. If your creature cannot be in repose, then it’s a bad design.’ When you see our creatures, you’re not going to say, ‘Oh, what a great movie monster.’ You’re going to say, ‘What aquarium, what specimen jar did that thing come from?’ They need to look entirely possible in their impossibility.” He’d been watching nature documentaries. “The worst thing that you can do is be inspired solely by movie monsters. You need to be inspired by National Geographic, by biological treatises, by literature, by fine painters, by bad painters.”

At Lightstorm, del Toro met first with Callum Greene, a British producer. Greene warned him that, without discipline, his budget could easily exceed Universal’s limit of a hundred and twenty-five million dollars. Greene had identified thousands of moments in the script where special effects would be employed.

Most of them, del Toro declared, required C.G.I. “Animatronic effects don’t look good in daylight,” he noted, and much of the movie would be shot in foggy snowscapes. He would be adopting an “Eastern palette,” in which whiteness connoted death. “Also, a physical approach doesn’t lend itself to the way I want to depict the creatures that much, because I want them to look very heavy. You’d have to do multiple core molds, and—you know how it is—the heavier the puppet is, the easier it breaks down. On set, you always end up saying, ‘Do not hit the deadly monster too hard, or it will break!’ ” When possible, del Toro said, he would initiate a shock sequence with physical objects, to ground the viewer in something real. The Old Ones are first seen as corpses, and Mike Elizalde could make those at Spectral Motion.

Del Toro wanted to shoot in Canada, which offered tax rebates. Greene proposed filming outside Vancouver: “You’re looking at mountains covered in snow every day.” But, he warned, “every night with two hundred people on per diem in a hotel is money.”

“We’re going to shoot there for a long period of time,” del Toro insisted. Otherwise, “you take away the scope instantly, and then you are doing a fucking Hallmark movie-of-the-week.” He also insisted on having two weeks to shoot landscapes in Antarctica, where, he noted later, scientists had recently mapped a massive mountain range hidden under ice.

He told Greene that digital-effects houses needed to understand that each Shoggoth had at least “eight permutations.” He said, “Let’s say that creature A turns into creature A-B, then turns into creature B, then turns into creature B-C. And by the time it lands on a guy it’s creature E.” He discussed one grisly Shoggoth transformation: “It’s like when you grab a sock and you pull it inside out. From his mouth, he extrudes himself.”

Del Toro then visited his art team—guys who nodded in unison when someone said, “You know how sea cucumbers puke their insides out to evade predators?” The veteran was Wayne Barlowe, a mild, bespectacled man in his fifties; he had collaborated with del Toro on “Hellboy” and had helped define many of the creatures in “Avatar,” including the Great Leonopteryx, the flying beast that Jake Sully tames on the planet Pandora. Barlowe still draws with pencils, and he sat in a sunny corner room. He had been sketching Cthulhu in a surprisingly soft hand. In his rendition, many appendages emanated from a central vertical column; it had the majesty of a redwood tree. When del Toro looked at it, he said, “I love the idea of the floating things!” Cthulhu was surrounded by satellite parasites, just as some sharks are haloed by schools of fish. Barlowe said that he was going for a “regal look,” and pointed at the creature’s neck. “It’s like an Elizabethan collar!” del Toro said, smiling. “Great.”

“Yeah,” Davis said. “When it’s forming, instead of just forming eyes, maybe it’s bubbling like mud, or pudding, so you have these sockets forming but no eyes yet. Then it gets one eye and has this cavernous companion. Mummies always freak me out because they have sockets but no eyes.”

“I hadn’t noticed,” del Toro teased. “Lovely.”

Allen Williams was the neophyte; del Toro had hired him at Comic-Con, in July, after seeing his illustrations on display. Several of Williams’s sketches were inspired by marine life: a morphing Shoggoth looked like giant jellyfish sliding across the Antarctic ice. It would be especially creepy, Williams said, if the viewer could see innards “vaguely moving under membranous material.” Del Toro nodded. Pointing at a creature with a profusion of fins, he said, “I like this, because it’s very much like a lionfish”—one of the weirdest inhabitants of a coral reef.

Though del Toro was enthusiastic about Williams’s work, he admonished him for incorporating too many signs of “infection or disease.” “These creatures are like Ferraris,” del Toro said. He sliced the air with his hands, suggesting aerodynamic contours. “The Old Ones didn’t create shitty machines.”

Peter Konig, who also designs characters for video games, sat in a pitch-dark room, before a glowing screen. His work was sharply etched, like Egyptian hieroglyphs. He had been playing around with symmetry, and showed a Shoggoth that appeared to be perched on spindly legs. With a click, he flipped the image upside down, and the legs became long arms, like those on a monkey.

“The silhouette works both ways,” del Toro said.

Next, Konig showed a Shoggoth whose tentacles were surging from what resembled a long, retracting foreskin. The creature had dozens of eyes, randomly placed, like those on a potato.

“Dude,” del Toro said, laughing. “It’s like a botched circumcision!” He told Konig that he was banning phallic imagery—the most obvious sign that an alien was designed by a nerdy Homo sapiens.

Del Toro told me that the group was off to a great start, but he was eager to impose discipline. “I will ruin their lives,” he joked. “There is no rhythm, and everything is too busy.”

Even though del Toro’s team had three months to experiment, the challenge was immense. The frozen city, for example, could emerge only after the artists had settled how the Old Ones moved, ate, and slept. “If you spend enough time strolling in the street—seeing a cathedral, seeing a door opening and closing in a building or a car—you understand the ergonomics of human beings,” he said. With a few key shots, del Toro needed to conjure, wordlessly, the lives of the aliens.

He also had to master 3-D. He had been studying “Avatar” on his laptop, and praised the “crystalline depth” that Cameron had created for Pandora. He said, “What is really great about 3-D is not what comes at you but the depth—what I call the ‘aquarium effect.’ ”

The digital spectacle of “Madness” was worlds away from the days of collodion scars and rubber suits. I asked him if technology was effacing his art. “The great consolation always comes in the form of Hitchcock,” he said. “Hitchcock did 3-D, wholeheartedly, with ‘Dial M for Murder.’ He would try every gimmick, every lens, every camera mount. He’s the patron saint for my proclivities.” With some embarrassment, he noted that, at Comic-Con, he had introduced a line of “Pan’s Labyrinth” figurines. “Hitchcock would have gone to Comic-Con,” he said. “He would have signed collectible shower curtains. He was a showman and an auteur.”

In early December, on the evening be fore del Toro presented his vision for “Madness” to Universal, he was fretting at Bleak House. The mansion had been expanded since the summer. The French doors had been dismantled, and a new hallway led to the Rain Room, a red parlor whose sole window was not a window at all. Old-school effects behind the glass—a mirror, a projector—insured that it was always a dark and stormy night.

The effect mimicked a similar window in the Haunted Mansion at Disneyland. A few months earlier, del Toro had announced plans to develop a feature film based on the attraction. Like “Frankenstein,” a haunted-house movie was something he had contemplated for years, but he wanted both projects to be realized after “Madness.” He said, “Seriously, I’ve been in preproduction between ‘The Hobbit’ and ‘Madness’ for two and a half years.” He could handle “only so much foreplay.”

Del Toro was pallid, and it did not look as if he had continued losing weight: he was still wearing black sweats. He went into the kitchen and rummaged through the freezer. “Want a Popsicle?” he said, taking one for himself. His lips were soon stained red.

The designs created at Lightstorm had been delivered to Bleak House, and del Toro’s assistants had prepared presentation boards. They were on a kitchen counter, and del Toro began going through them.

The aquarium look that he had spoken of at Lightstorm had clearly become a governing metaphor. “I wanted the whole city to be like an abandoned coral reef,” he said. He showed me an image of a cavernous interior space. Everything was tubular and encrusted with skeletal remains—abandoned tools. “A coral reef is a shitload of skeletons fused together, right? All the technology those creatures have, all their technology is organic. You and I use metals, plastics. These creatures don’t have weapons or chisels. They create other creatures as tools.”

The architecture of the Old Ones was based on “curves and cylinders,” he said. “There are no steps, no ramparts. And the edifices are not at all human. There’s no balconies or doorways.” The city resembled a labyrinth of pneumatic tubes.

As del Toro had promised, the city’s form intimated the silhouette of the Old Ones. “They are essentially suppositories,” he said. “They sort of torpedo through the tubes.” But didn’t Lovecraft write that they had wings? Del Toro smiled: wings and tentacles had been hidden inside the ovoid silhouette. An Old One opened up “like a Swiss Army knife.”

The oceanic motif was particularly evident in the design of the Old Ones. Del Toro’s enthusiasm for the lionfish had endured, and the aliens’ wings echoed their flamboyant fins. In motion, he explained, the Old Ones would appear buoyant—“unbound by gravity.” As the camera tracked them caroming around the city, the viewer would feel disoriented, like a panicked scuba diver inside a cave. “We designed the creatures in such a way that they can go forward or backward, or hang, or be vertical, and they still make sense,” he said. Beckoning me into the Rain Room, he opened his laptop and showed me a rough digital rendering of an Old One. As Peter Konig had done at Lightstorm, he flipped the image upside down; then he flipped it on its side—in all formations, locomotion was plausible. “It has no forward and no backward,” he explained. “If this moves forward or backward in a way that I can recognize, it’s boring. Have you seen a Spanish dancer move in the water? They go like this”—his hand made an undulating motion. “It’s muscular and creepy.”

The Shoggoths, he said, performed an even more fluid transformation. Creating them would push digital technology to the limit: you weren’t just tweaking a polygon; you were ditching one polygon for another. Del Toro had commissioned several maquettes from Mike Elizalde. The cast-resin monsters rested on beds of artificial snow, and hovering Shoggoths were held aloft with thin metal poles. The models were poignant relics of twentieth-century technology, but they helped connect del Toro’s current vision with the tradition of Forrest Ackerman. These were the next Famous Monsters of Filmland.

The Shoggoths had a racecar sheen. “They are pristine,” he said. “They are functional. They are not asymmetric. Symmetry is efficiency. And these guys need to be efficient.” He wasn’t sure yet if the Shoggoth palette should be “pearlescent” or “circulatory”—reds and blues. Since the Shoggoths could mutate into anything, there was no fixed silhouette, but many would feature a “protoplasmic bowl,” an abdomen-like area from which new forms could sprout. One maquette was a disorienting twist on classic Lovecraftian form. It looked like a giant octopus head with tentacles jutting from the top and the bottom—a fearful symmetry. “That’s my belly in the middle,” del Toro joked.

In another maquette, the Shoggoth had sprouted two heads, each extending from brontosaurus-like necks. Their skulls could be smashed together to destroy victims. “The idea is to create craniums that function as jaws,” he said. The Shoggoths would often create ghastly parodies of human forms; as they pursued the humans, they would imitate them, imperfectly.

Having read the script, I knew that the body count would be high. (“BAMMMMM!!!!! A massive Shoggoth explodes out from the tower!!!!! It grabs and devours Gordon in mid-sentence!”) But del Toro promised that the film was “not gory.” Victims would be “absorbed” by the aliens in ways that were “eerie and scary.” He explained, “When you watch a documentary of a praying mantis eating the head of its mate, because of the complexity of the mouth mechanism, you’re fascinated. It’s a horrible act, but you’re fascinated.” Though he wouldn’t be spattering blood, he said that he needed to fight Universal for an R rating, “to have the freedom to make it really, really uncomfortable and nasty.”

The meeting at Universal, he said, was at ten-thirty: “I’ve never been this nervous going to a meeting. This invested.” He added, “There are certain rules to dating a movie. You try to fall in love when it’s a reality, and try not to be completely head over heels on the first date. But I’m hopelessly in love with the creatures.”

Adam Fogelson and Donna Langley, the top executives at Universal, would attend, as would James Cameron. Del Toro said, “He’s supporting what I want. He said to me, ‘You did this with five guys in ten weeks? That’s astounding.’ ”

Del Toro indicated that he would not be willing to make radical adjustments to his vision. “I don’t want to make a movie called ‘At the Mountains of Madness.’ I want to make this movie. And if I cannot make this movie I’ll do something else.” He paused. “It’ll be horrible.”

Fogelson was impressed with the presentation. “The sense of scope, the sense of danger, and just the sheer popcorn commercial appeal of the creatures that he was presenting to us were a sight to behold,” he told me. “At each step, he wowed us, and, to be candid, he knew— and we all knew—that a ‘wow’ was required to keep this movie moving forward. It’s a big bet.” Still, Universal wasn’t quite ready to give the project a green light. Del Toro went to another meeting, and then another. As of late January, the project remained potential energy. Del Toro was confident that his creatures would one day roam the multiplex, but I remembered that he had called Hollywood “the Land of the Slow No.”

On that December night at Bleak House, I noticed that del Toro had moved some of his journals from the bathroom safe to a shelf in the Rain Room. I asked to see early sketches for “Madness.”

The notebook was from 1993. He turned the pages, stopped, and smiled. “Look!” he said. It was an image of one of the explorers falling into icy water. An inky creature lunging at him looked breathtakingly similar to the Shoggoth with symmetrical tentacles. Del Toro’s monsters had inhabited his mind for nearly two decades. From the beginning, del Toro had imagined that his creatures, unlike Lovecraft’s, would have a fatal vulnerability—one that explained why the horrible beasts had remained trapped in Antarctica. Salt water: it dissolved a Shoggoth like a slug. ♦